In adventive polyembryony, an embryo develops directly from the...

Adventive polyembryony is a type of apomixis in which extra embryos develop directly from the diploid sporophytic cells of the ovule lying outside the embryo sac.

These diploid cells typically belong to the nucellus or the integuments. Examples include Citrus and Mangifera, where nucellar or integumentary cells protrude into the embryo sac and develop into embryos.

Answer: nucellus and integuments